Electric musical instrument.



M. LSBVERY an G. B. sINcLA'IR.

ELECTRIC MUSICALINSTB-UMENT. uPLIcA'rIon FILED. 11:15.23, 190s.

Patented July 28, 1914.

'IIUIIIIIIIIIIIIFIIIIIH= Figi Invenllfm',

M. L. SEVBRY du G. B. SINGLAIR.

ELECTRIC MUSICAL INSTRUMENT.

nrLIoATIoN rI-Lnn rimas, 190s.

1 ,104,939. Patented July 28, 1914 2 SHEETS-SHEET 2.

v Immo/w@ Melvn L. SeveQ/yjy M 2 7% Gemfgel. SLi/claw? UNITED STATES' .PATENT OFFICE.

MELVIN I.. snvnmn or ARLINGTON HEIGHTS, AND GEORGE B. sINoLAm, or f 'WINTHROP,'MSSACHUSETTS, ASSIGNORS TO CHORALCELO INIANUIEAC'IU'R- ING COMPANY, A CORPORATION OF MAINE.

ELECTRIC MUSICL INSTRUMENT.

Specification of Letters Patent.

Patented lily 28, 1914:.

Application led February 23, 1906. Serial No. 302,331.

To all whom tjmay concern A Be it known that we, MELVIN L.y SEVERY, of Arlington Heights, in the countv of Midldlesex and Commonwealth of Massachusetts,

5 and GEORGE B. SINCLAIR, of Winthrop, in

the. .county of Suffolk, in said Commonwealth, both citizens of the United \States, have invented certain new and useful Improvements in Electric Musical Instruments,

loof which the following is a full, clear and o exact description.

This invention pertains to that class of musical instruments wherein arseries of J' sonorous bodieshsuch as-steel or iron strings, are vibratd by the pulsatory magnetic attraction of electromagnets; the magnetic,

ulsations being produced by a -circuit reaking or switching device consisting of l uniformly rotating members formed with alternate conducting and non-conducting sections contacting with suitable brushes.

The object of our invention is, first, to neutralize the effect of the lap between said sections and brushes; for we have discovered that when the conducting sections are made equal in span to the non-conducting 'sections as has always previously been the practice, the contacting thickness of a brush will, in action, so operate that the current will be vdelivered to the associated electromagnet forI a longer fraction of time than it will be cut out therefrom. In consequence of this, the time of action of the magnet would not correctly coincide with the time of approach of the sonorous body toward said magnet.

yThis necessarily diminishes toa substantial degree the strings amplitude of vibration, and hence its loudness of tone, as compared with what it might be were the pull of the magnet to coincide exactlywith theinward swing of the string; or at least not to eaceed the same.

Our improvement for overcoming this defect consists in shortening the arcs of' the conducting sections relative to the non-conducting sections sutliciently to render the dead. instants of theimagnets equal to, or

application. To the extent -that suc In our Patent No. 814,878, we disclose a device for this purpose in which each toothed member has two brushes contacting'there-v with a tooths distance apart and connected with two magnets at oppositesides of the string or other sonorous body. We have means of a Fsingle make-and-break brush.'

found, however, that itis practically ,impossible to so perfectly keep the ytwo brushes in4 adjustment .as1 to prevent them from interfering more or less with each other in their effects uponv the string between. Byv alternately energizing the two magnets of l' a string with a single brush, such diiiculty is removed and no matter how-much the brush may wear no injurious effect is caused thereby.`

y The art or method ofproducing'musical tones necessarily set forth in describin the apparatus of this application, isreserve for copending applications, beings'et forth and claimed in different scope in our co-pending applications Serial No. 273,202 filed August 7, 1905, Serial No. 379 714, filed June 19, 1907,- and Serial No. 53 ,257, tiled January 1 0, 1910. y

In our joint application, Serial N o.

563,437, nled May .25, i910 is further dis;`

closure and descriptionof featuresinore or less in common with features of this resent matters are claimed in said application Serial No. 563,437 they are not claimed herein, but

-are reserved to said other application.

the construction disclosed by Fig. 2.

In Fig. 1, 1 designates a magnetically sensitive string similarto that of a piano; 2 is -an electromagnet .having a pole presented to said string; 10 is a uniformly rotated disk having conducting sections 12 andI high-resistance' sections, 13; 26 is the brush 'slightly greater than, their energized instants; and so cause the magnetic pulsations 50 'to synchronize with the strings vibrational f swings. y v

f 'f Our second i improvement relates to a Aineans forfpositively actuating a .sonorous f body throughout its entire vibration by 2; thence through engaging the periphery otr said disk, and

is depressed, the 4current passes from the source 30 through'the wire 33 to the magnet the wire 23, contacts 22,21, wire 25.brush 26, disk 10, shaft 11, brush 31 ^and wire 32 back to said/source. Of course the instant a tooth o'r conducting section 12 passes energized; and the instant a non-conducting or high ,resistance section 13 reaches the" brush 'the magnet is demagnetized;"=thus causing the string to be alternately attracted and released in unison with its designed rate of vibration.

In accomplishing vention we lengt en each space 13 until each toothy 12 is substantially shortened as compared with what it would bev teeth and spaces made all equal. In other words, the angular distance included between the dottedlines 15, Fig. 1, which represents the length of arc when the spaces 13 and teeth 12 arefequal, is lengthened to thatdembraced between the dotted lines 16, thereby taking from the peripheral length of each tooth andadding the same to the spaces. In consequence, when the edgek of a tooth 12 reaches the heel of the brush 26,

" current immediately flows through the same,

t and continues until the opposite edge of the tooth passes out of contact ,with 'the toe cf the brush; and the time during which the current is thus flowing willexactly equal the time during which no current is iiowing; providing the hi-gh resistance sections 13 are longer than the conducting sections 12 by twice the lap of the brushl 1n this vman- V-ner the energized intervals of the magnet 2 will notexceed the non-energized` inter- #vals of the same, and, the stringy willnot only ,bef ositively Vmoved in one direction of its swing", but wili receive no hindering attraction during any part of its opposite swing. Of course no such hindering action williccur if ythe teeth are made even shorter than above described, but the positive action of the string will be lessened accordingly. Hence it is est to proportion the same as above set forth.

To provide positive actuation of the string in each swing of its vibration, and accomplish the second function of our invention,

a core 5 islocated at the opposite side of `the stringufrom the magnet 2, and a coil 4 placed on a part of said core andnonnected with a suitable source of electricity; either the `one already referred to, or to a separate surce 9,4 Upon the lower section ofthe core 5 is a coil3 connected `by means ofnthe wire 35 'to the wire 33, and by means of the wire 24 to, ythe \wire' 23. The wires 33,' 35 r`being .joined by the wire 34 to the electromagn'et the brush 26 the magnet 2 is` were the 2, and the wire 23 being connected with the pposite terminal of the said magnet 2,

into touch, both the magnet 2 andthe coil 3 are energized. The coil 3 being adapted by its winding and the direction of current delivered thereto to give to the core 5 a`V clarity opposite to the latters normal po arity, upon said coils being energized thepolarity of said core will be thus neu- `tralizednand there will consequently be n0 Mmagnetic pull given by it to the string 1. But the magneti-2 being energized as above stated, while the core 5 is impotent, the string will be attracted by said magnet.

y y. Then, at the instant the disk 10`presents a the first object of our innon-conducting 'section to the brush 26, the circuit to the magnet 2 and the coil 3 is broken, said magnet land coil demagnetized, and the core' 5 permitted again to attract the string. In this manner, the string is alternately attracted by the magnet 2 and the core 5, and so given a positive actuation throughout its entire vibration. There being some lost energy in this arrangement, we have improved thereon in the way of simplicity of construction and economy of current. rThis form of our invention is shown in Figs. 2 and 3, where 1 designates the string, and 40 and 41 two electromagnets iixed at opposite sides of said string. Said vmagnets 40, 41 are so wound that the magnet 41 will have a magnetic" pull considerably less than that of the magnetv40, when current is simultaneously delivered to both,-as one-half. Consequently, when current is supplied to both magnets, the stronger pull of the magnet 40 will attract the string towardl it more powerfully than the other magnet. Then when the current is cut out from the magnet 40, the magnet 41 will attract `the string toward itself; and in this way, the string will receive al pull in altermately opposite directions. l

The course of the current is as follows: The key 2O being depressed to put the conta'c'ts 21, 22 into .touch with each other current flows from the source 30 through the wire 45, electromagnet 41, wires 44 and 47, said contacts, and wire 46' back to said Lsurce. This is -the only circuit traversed by the current when the insulating, or hightouch with the brushes 26.` When, however, the conducting sections, or teeth, 12 reach the brushes '26, then in addition to aboverecited circuit, each electronagnet 40 whose key is depressed will receive current through the wire 45, and thence through lthe wire 32, brush 3,1, shaft 11, disk and tooth 10, 12, brush 26 `anch wire 42; the return bein through the wires 43, 47, contacts 21, 22Jan wire A46 back to the source. a V

ile we have shown. and i described magnetically attractive strings as our sonowhenever the contacts 21, 22 are broughtresistance sections 13 of the disks 10 are in 50 X ative motion i ro'us bodies, itis quite evidentthatour invention isequally applicable to many other .kinds of` magnetlcally actuated sonorous bodies, as bars, disks, reeds, tubes etc. We do not, therefore, limit ourselves to any particular kind of sonorous body, butJdesire to be: protected in the broadest interpretation of our invention. A

In the foregoing description the lag of the string or other sonorous body as related to the impelling force, is not noted,

- for the reason that suchlag is more or less av `controverted matter, and its injection would simply tend to confusion. The essential point is that whether the two be v absolutely in phase or there be a lag of the strmg or sonorous b'ody,\-F thef relations/hip necessary to `generation of e proper tone is madeand maintained co stant, and the desired result is thereby assured. If there .be such lag, it must be uniform, and the :movement if commencing later will finish correspondingly later; hence the effect will be that the length of time during which the attractive force is maintainedwill precisely equal the, length of time during which the movement in response to that attraction continues. The foregoing description and the claims are hence to be standing.

What we clalm as our lnvention and for read with this underwhich We desire Letters Patent is as follows,

tricity, a uniformly g1. vThe combination of a magnetically attractive sonorous body, an electromagnet presenting a pole thereto, a source of clecrotated member having alternate sections-.of high andflow resist-y ance, al brush "contacting therewith, and connections'between said source, brush, member "and magnet, the peripheral .length ofy said low reslstanc'e sections being less than that of the high resistance sections by subi. of electricity,

' an electromagnet adapted v and low resistance,-

relative motion, -sald source, .65

stantially twice the lap of the aforesaid .Q. The combination of a sonorous body,

anele'ctromagnet forfits actuation, a sourcea member having alternate sectiqns of high and-low resistance, va brush ncntacting therewith, means for givingrelto said member and brush, and

connections between said source, brush, member andvmagnet, the lengthof said low regsistance sections being substantially les's\ than that of thehigh resistance sections by 3, The combination of la an amount twice the lap of said brush.

sonorous body, to vactuate the tricity, a cylindrical ate sections of high a vbrush contacting with said member, said brush and member having and connections between brush,- member and magnet, -`the same', a'source of e member having alter peripheral length of said low resistance seckey maintains said tions being such that each contact shall be made with its brush throughout an interval equal in duration to substantially `the Whble of lthe, time consumed by lthat part of the vibration of said sonorous body wherein the latter is swung toward said magnet', but for no longer time'. c y

4. The combination of a magnetically attractive sonorous body,

berA having alternate high and low resistance sections, a brushcontacting with said member, a sourceof electricity, connections between said magnets, brush, source and member, and a key controlling said connections, said parts being'disposedVupon the depression of said key, to bring both of said magnets in circuit simultaneously when one of the conducting parts of said member engages .said brush, and .to cut out one of said two electromagnets adapted to actuate the same, a rotating mem- 7 magnets when the non-conducting parts of 6. Thecombination of a magnetically aty tractive sonorous body, an electromagnet disposed with said body Ain its field, megans for delivering timed electric said electromagnet embracing a circuit, and a single current-interrupting device having a single brush, a second electromagnet disposed with saidbody in its field but opposite to and in substantial alinement with the first pulsations to electromagnet, and connections ,for deliverlmgfcontlnuous current to the second electromagnet, the windings'of said electromagnets being unlike in reslstance and causing the second electromagnet-to be weaker than "an, electromagnet thefirst electromagnet when both are simultan'ebusly energized.

7. The combination of a magnetically attractive sonorous body, an electromagnet disposed with said body in its field, means for delivering timed electric pulsations. to said electromagnet embracing a circuit and' a key.contr.olling the circuit, a second electromagnetdisposefd with y,said bod'y 1n its field but opposite to and in substantial alinet ment with the first' electromagnet, and connections for delivering.L cjntlnuous ,current to the second electromagnet so long as said electromagnet being circuit closed, the first Wound with much lower po' having a magnetic strength in excess of that of the latter when both are simultaneously. energized.

8. The combination of a magnetically attractive body,

two electromagnets presenting their poles at opposite sides of said body, a rotating member having' its ,f periphery formed 'with alternate highl and low resistance sections, a brush contacting vwith'said periphery, a source of electricity, a contact and a key controlling it, connections between said key and both of said magnets, a connection between said contact and one poleV of said source, a connection between the opposite pole of said source and said member, a connection between said brushy and one of said magnets, and a connection between the other of said magnets and said opposite pole. Q9. The combinationtowa magnetically attractive isonorous body, two electromagnets disposed to actuate the same from opposite sides, a rotating disk having alternate sections 'of high and low resistance, a single brush contacting therewith, a source of electricity, and connections between sald source, y

electromagnets, brush and disk, including a branch circuit for one of the electromagnets, said disk and single brush being arranged to deliver to' one of said electromagnets,inter-'l rupted currents,

the other of said electromag` nets being energized by an uninterrupted' current, whereby said magnets are adapted alternately to attract said sonorous body in opposite directions.

1Q. tractive sonorous body, two electromagnets disposed with said body in their fields but inzopposition to each other and in substantial alinement,'a rotating circularmember having its periphery divided into alternate sections of high and low resistance, a brush contacting with said periphery, ya source of current, a circuit comprising two branches,

l, The combination of a-magnetical1y at* one branch including said brush,rotating45 member and one of said electromagnets, and the other branch includingI the other elec# tromagnet, said electromagnets being unequal in attractive power, and a circuit controlling device in the common section of said.

circuit.

In testimony that we claim the foregoing invention, we have hereunto set our hands this 16th day of February, 1906.

MELvrN L. SEVERY. GEORGE Le. sINoLAIE.

Witnesses: y y

LOWELL M. MAXHAM, A. B. UPHAM. 

